Back in the days when dinosaurs roamed the earth, my roommate was working on a commercial app that was a music composition and sequencing tool. One night I heard some unusual music coming from his room, and a few moments later he ran out all excited. It turns out that he'd had a bug in his code, and the music we'd been hearing was the program playing itself: interpreting its own code as music data.
What was surprising, though, was how coherent it actually sounded as music. There was, for example, a perceptible beat. We always wondered whether this was due to the structure of the executable code, or because of the way the program interpreted its data. Unfortunately he was never able to reproduce the bug in quite the same way.
I had a really, really odd experience when I was very young -- probably no older than 6 or so. I was on a 386 running MS DOS 5 and at the time, I was hooked on a game called "Pilgrim's Quest". I was also in the habit of breaking edit.com out on everything I could get my fingers on, and binaries were no exception. I had no idea what I was doing (otherwise I would've been using debug.com), but I would delete things, type random characters, etc. One day, I took edit.com to the binary for Pilgrim's Quest, and proceeded to mess with it, rendering it useless. Except, it wasn't useless. When I ran it, the display was messed up, but pressing keys caused notes to play. To this day, I can't figure out why this would've happened -- I know of no functionality in the game that played single notes (although, to be fair, I don't remember if it played a note and then stopped or continued playing it indefinitely -- this was a long time ago), and I can't see how one could stumble upon that.
I really wish I knew what the hell I did, as that was the first time I ever made the computer do something it wasn't intended to do, even if it was not my intention.
I used to listen to RAM dumps from an HDTV tuner card I was reverse engineering to try to find its audio buffers. Naturally the image buffers always sounded interesting. I eventually wrote a rudimentary ALSA driver for it.
You can get sounds that sound like an alien machine by taking some super-noisy image or executable data and slowing it down several times using a high-quality resampling algorithm.
I'm reminded of one of my favourite pieces of "music", the Symphony For Dot Matrix Printers. Basically, a couple Canadians acquired a crop of old printers, wired them up to some equally old computers, and figured out how to feed them all sorts of interesting printing instructions. Listening very carefully to the resulting sounds, they figured out how exactly to place microphones to capture all the fascinating sonic nuances, organizing the printers and their noises into various instrumental roles. They composed a surprisingly musical work for the printers to play, as though they were an orchestra, which was performed live and recorded. The recording is rather difficult to track down, but is quite a treat for enthusiasts of real "computer music".
They sound like printers. But they sound like printers, re-imagined by people who hear music in everything.
I actually stumbled across this while experimenting with libsndfile(www.mega-nerd.com) I built a .NET wrapper around it for converting telephony .vox files to a more user friendly format. In the process of beta testing I found you can feed any bits you want to it and it will spit out a "wav" or other of its supported formats to be played by any media player. I guess I will have to revisit that project for musical inspiration...
I remember being able to distinguish bitmaps in Apple II games saved to tape (floppy disk drives were too expensive for me at that time). This brings me back memories.
There was also a radio program that transmitted audio on one channel and computer programs on the other one, broadcast from the local university radio on, IIRC, Saturday afternoons. Those programs were for MSXs, so I never loaded them.
I assumed they were UI elements. I haven't actually seen MS Paint in ten or more years, but I'm guessing it has many widgets that are square buttons with something inside, so the image data would appear as repeating patterns of identical length and have at least somewhat similar content (because everything is in a bordered box, and there's probably an "up" and "depressed" version of each, leading to nearly identical sounds being side-by-side in the data).
That's just a guess though. One would probably need to disassemble it and roam around a bit to be sure.
Another interesting thing to do is play back image data as audio. I used to use this for wild sound effects in tracks I was making about 15 years ago. Never did get to the point where I could play around in photoshop to deliberately create sounds, but I suppose one could if you made a study of it.
The "tune" on soundcloud.com is mspaint.exe as 8bit signed PCM, but modified - try importing it in f.e. Audacity and you will notice that quite some editing (fade ins/outs, time stretching etc.) has been applied to the soundcloud.com version.
This works in Audacity, and probably any other audio program that can import raw PCM data. I imported it as 22050hz 8-bit stereo audio in Adobe Audition, but it seemed to sound mostly the same in Audacity.All I did to the audio was master it slightly to make it sound less harsh to the ears, as well as remove a long section of noise.